There is lots of material online that talks about the pros of niche marketing and also on how to find a profitable niche online. Hunting down small online niches could prove to be profitable especially to small businesses. While this is true, many still overlook the need to expand their search to uncover new unexplored market niches.
Anyone who has done some form of niche marketing would immediately know that keyword research is crucial for any success. Overture, GoodKeywords and WordTracker are some useful free tools people often use. Some have tried using Google to search and verify the amount